Battery pack

Abstract

A battery pack (1) comprises: a battery module (10); a pack housing (20) for accommodating the battery module (10); and an upper case (30) that is at least partially positioned between at least a portion of the battery module (10) and at least a portion of the pack housing (20).

Description

Battery pack

[0001] The present invention relates to a battery pack.

[0002] In recent years, various battery packs have been developed. A battery pack includes a battery module and a housing that houses the battery module. The battery module has multiple battery cells electrically connected in series, in parallel, or in a combination of series and parallel.

[0003] Patent Document 1 describes an example of a battery module. This battery module includes a plurality of battery cells, a case that houses the plurality of battery cells, and a cover that can be attached to and detached from the case. A space exists between a portion of the case and a portion of the cover.

[0004] Patent Document 2 describes an example of a battery pack. This battery pack includes a case that houses multiple battery modules. The case has a lower housing and an upper housing. The lower housing includes a dividing beam that divides the space that houses the multiple battery modules into multiple sub-cavities.

[0005] Patent Document 3 describes an example of an automobile power battery. This automobile power battery has an automobile battery body, an inner housing that covers the automobile battery body, and an outer housing that covers the inner housing.

[0006] Japanese Patent Publication No. 2021-072177 Chinese Utility Model No. 210489699 Chinese Utility Model No. 208489303

[0007] In a battery pack, relatively high-temperature gas may be generated from the battery module when abnormal heat generation occurs in a battery cell. If the gas generated from the battery module is blown directly onto the housing, it may be difficult to improve the heat resistance of the battery pack.

[0008] One example of an object of the present invention is to improve the heat resistance of a battery pack. Other objects of the present invention will become apparent from the description of this specification.

[0009] An aspect of the present invention is as follows: 1. A battery pack comprising: a battery module; a housing that houses the battery module; and a partition member located at least partially between at least a portion of the battery module and at least a portion of the housing. 2. The battery pack described in 1., in which the partition member is spaced apart from at least one of the at least a portion of the battery module and the at least a portion of the housing. 3. The battery pack described in 1. or 2., in which a space exists between the partition member and at least a portion of the battery module, or between the partition member and at least a portion of the housing. 4. The battery pack described in any one of 1. to 3., in which the partition member is heat resistant.

[0010] According to the above aspect of the present invention, the heat resistance of the battery pack can be improved.

[0011] It is a top view of the battery pack according to the embodiment. It is a cross-sectional view taken along the line AA in Fig. 1. It is a cross-sectional view of the battery pack according to the first modified example of Fig. 2. It is a cross-sectional view of the battery pack according to the second modified example of Fig. 2.

[0012] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by similar reference numerals, and descriptions thereof will be omitted as appropriate.

[0013] Fig. 1 is a top view of a battery pack 1 according to an embodiment. Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1. For the sake of explanation, the pack upper case 24 and the plurality of upper cases 30 shown in Fig. 2 have been removed from Fig. 1.

[0014] In the embodiment, the battery pack 1 is mounted on an automobile. Specifically, the battery pack 1 is mounted between the front and rear wheels of the automobile. Unless otherwise specified, the following description will be given assuming that the battery pack 1 is mounted on an automobile. However, the battery pack 1 can also be used for purposes other than automobiles.

[0015] For the purpose of explanation, the X, Y, and Z directions are shown in each figure. The X direction indicates the front-to-rear direction of the battery pack 1. The Y direction is perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery pack 1. The Z direction is perpendicular to both the X and Y directions. The Z direction indicates the up-to-down direction of the battery pack 1. The arrows pointing to the X direction, the Y direction, and the Z direction indicate the front, left, and up directions of the battery pack 1, respectively. In FIG. 1, a white circle with a black dot indicating the Z direction indicates that the arrow pointing to the Z direction extends from the back of the page to the front. In FIG. 2, a white circle with a black dot indicating the X direction indicates that the arrow pointing to the X direction extends from the back of the page to the front. The relationship between the X direction, Y direction, and Z direction and the front-to-rear direction, left-to-right direction, and up-to-down direction of the battery pack 1 is not limited to the example described in the embodiment.

[0016] In the embodiment, the front-rear direction, left-right direction, and up-down direction of the battery pack 1 are determined by the vehicle in which the battery pack 1 is mounted. The X direction, Y direction, and Z direction respectively indicate the front-rear direction, left-right direction, and up-down direction of the vehicle. The arrow pointing to the X direction, the arrow pointing to the Y direction, and the arrow pointing to the Z direction respectively indicate the front, left, and up directions of the vehicle. However, the relationship between the front-rear direction, left-right direction, and up-down direction of the battery pack 1 and the front-rear direction, left-right, and up-down directions of the vehicle is not limited to this example.

[0017] Hereinafter, as needed, the side indicated by the arrow indicating the X direction will be referred to as the +X side, and the side opposite the side indicated by the arrow indicating the X direction will be referred to as the -X side. Hereinafter, as needed, the side indicated by the arrow indicating the Y direction will be referred to as the +Y side, and the side opposite the side indicated by the arrow indicating the Y direction will be referred to as the -Y side. Hereinafter, as needed, the side indicated by the arrow indicating the Z direction will be referred to as the +Z side, and the side opposite the side indicated by the arrow indicating the Z direction will be referred to as the -Z side.

[0018] The battery pack 1 will be described with reference to FIGS. 1 and 2. FIG.

[0019] As shown in Figures 1 and 2, the battery pack 1 includes multiple battery modules 10, a pack housing 20, and multiple upper cases 30. As shown in Figure 2, each battery module 10 includes multiple battery cells 100 and a module housing 110. As shown in Figures 1 and 2, the pack housing 20 includes a pack lower case 22, a pack upper case 24, and a pair of pressure release valves 26. As shown in Figures 1 and 2, the pack lower case 22 includes a pack lower plate 22a and a pack frame 22b. As shown in Figure 2, the pack upper case 24 includes a pack upper plate 24a and a pack upper side cover 24b. As shown in Figure 2, each upper case 30 includes an upper plate 32 and a pair of side plates 34.

[0020] 1 , in this embodiment, four battery modules 10 are arranged in two rows and two columns in each of the X and Y directions. Hereinafter, as necessary, the battery module 10 located on the −X side and the −Y side of the four battery modules 10 will be referred to as the first battery module 10a, the battery module 10 located on the −X side and the +Y side of the four battery modules 10 will be referred to as the second battery module 10b, the battery module 10 located on the +X side and the −Y side of the four battery modules 10 will be referred to as the third battery module 10c, and the battery module 10 located on the +X side and the +Y side of the four battery modules 10 will be referred to as the fourth battery module 10d. However, the number and arrangement of the battery modules 10 are not limited to those described in this embodiment.

[0021] As shown in Fig. 2, in each battery module 10, the plurality of battery cells 100 are stacked in the Y direction. Hereinafter, as necessary, the plurality of battery cells 100 stacked in the Y direction will be referred to as a stack of battery cells 100. The dimension of each battery cell 100 in the X direction is the dimension in the longitudinal direction of each battery cell 100. The dimension of each battery cell 100 in the Z direction is the dimension in the lateral direction of each battery cell 100. The dimension of each battery cell 100 in the Y direction is the dimension in the thickness direction of each battery cell 100. The shape of each battery cell 100 is not limited to this example.

[0022] Each battery cell 100 includes a battery element and an exterior material that seals the battery element. The battery element has at least one positive electrode, at least one negative electrode, and at least one separator. For example, multiple positive electrodes and multiple negative electrodes are alternately stacked in the Y direction. At least a portion of the separator is located between adjacent positive electrodes and negative electrodes in the Y direction. For example, multiple sheet-like separators may each be located between adjacent positive electrodes and negative electrodes in the Y direction. Alternatively, a single sheet-like separator may have a zigzag shape that passes through the region between adjacent positive electrodes and negative electrodes in the Y direction. Alternatively, the positive electrode, negative electrode, and separator may be wound so that the separator is located between the positive electrode and negative electrode. In one example, the positive electrode, negative electrode, and separator are wound with both surfaces of one of the positive electrode and negative electrode covered by the separator. In another example, a stack including multiple unit stacks each including a positive electrode, a separator, and a negative electrode in this order may be wound. However, the winding structure of the positive electrode, negative electrode, and separator is not limited to these examples.

[0023] The battery cell 100 may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in a portion corresponding to a separator. An all-solid-state battery does not contain an electrolytic solution. Hereinafter, unless otherwise specified, the battery cell 100 will be described as a battery cell containing an electrolytic solution.

[0024] In each battery module 10, the multiple battery cells 100 are electrically connected in series, in parallel, or a combination of series and parallel. The multiple battery cells 100 are electrically connected to each other via positive and negative terminals (not shown) located on opposite sides of each battery cell 100 in the X direction, or via positive and negative terminals (not shown) located on either the +X or −X side of each battery cell 100. For example, the multiple battery cells 100 in each battery module 10 may be connected in series from the battery cell 100 located at the end of the stack of battery cells 100 on the +Y side to the battery cell 100 located at the end of the stack of battery cells 100 on the −Y side. Alternatively, the multiple battery cells 100 in each battery module 10 may be connected in parallel. Alternatively, multiple cell groups including multiple battery cells 100 connected in parallel may be connected in series.

[0025] 2, in each battery module 10, a module housing 110 houses a stack of battery cells 100. Specifically, a module lower plate 112 covers the -Z side portion of the stack of battery cells 100. A module upper plate 114 covers the +Z side portion of the stack of battery cells 100. A pair of module side plates 116 cover both sides of the stack of battery cells 100 in the Y direction. The module housing 110 further includes plates (not shown) that cover both sides of the stack of battery cells 100 in the X direction.

[0026] As shown in FIGS. 1 and 2 , the pack housing 20 houses multiple battery modules 10. Specifically, in the example shown in FIG. 1 , when viewed from the Z direction, the pack lower plate 22a has a generally rectangular plate shape with a pair of sides parallel to the X direction and another pair of sides parallel to the Y direction. However, the shape of the pack lower plate 22a is not limited to the shape shown in FIG. 1 . The multiple battery modules 10 are disposed on the +Z side of the pack lower plate 22a. The pack frame 22b is disposed on the +Z side of the pack lower plate 22a. When viewed from the Z direction, the pack frame 22b at least partially surrounds the space in which the multiple battery modules 10 are housed. Hereinafter, as necessary, the space surrounded by the pack frame 22b when viewed from the Z direction will be referred to as the housing space of the pack housing 20. In the example shown in FIG. 1 , when viewed from the Z direction, the pack frame 22b has a generally rectangular frame shape with a pair of sides parallel to the X direction and another pair of sides parallel to the Y direction. However, the shape of the pack frame 22b is not limited to the shape shown in FIG. 1 . 2, the pack upper plate 24a covers the multiple battery modules 10 from the +Z side. The pack upper side cover 24b extends from the outer peripheral edge of the pack upper plate 24a in the Z direction toward the -Z side.

[0027] 1, a pair of pressure release valves 26 are provided on the outer surface of the pack frame 22b on the -X side. When abnormal heat generation occurs in a battery cell 100, relatively high-temperature gas generated from the battery module 10 may be discharged into the storage space of the pack housing 20. This gas is discharged to the outside of the battery pack 1 via the pair of pressure release valves 26. However, the number and arrangement of the pressure release valves 26 are not limited to the example shown in FIG. 1.

[0028] 2 , each of the plurality of upper cases 30 at least partially houses each of the plurality of battery modules 10. Hereinafter, as necessary, the upper case 30 that at least partially houses the first battery module 10a will be referred to as the first upper case 30a, and the upper case 30 that at least partially houses the second battery module 10b will be referred to as the second upper case 30b.

[0029] The first upper case 30a will be described with reference to Figure 2. The matters described for the first upper case 30a are similarly applicable to the second upper case 30b, the upper case 30 that at least partially houses the third battery module 10c, and the upper case 30 that at least partially houses the fourth battery module 10d.

[0030] As shown in FIG. 2 , the upper plate 32 of the first upper case 30a covers the +Z side surface of the module upper plate 114 of the first battery module 10a. In the example shown in FIG. 2 , the upper plate 32 of the first upper case 30a is approximately perpendicular to the Z direction. However, the upper plate 32 of the first upper case 30a may be at least partially inclined with respect to the direction perpendicular to the Z direction. A protection circuit (not shown) electrically connected to the first battery module 10a may be provided on the upper plate 32 of the first upper case 30a. For example, the protection circuit may be disposed on the +Z side surface of the upper plate 32 of the first upper case 30a. By providing the protection circuit on the upper plate 32 of the first upper case 30a, the base area of ​​the battery pack 1 perpendicular to the Z direction can be reduced compared to when the protection circuit is provided on, for example, the pack lower plate 22a. The pair of side plates 34 of the first upper case 30a extend from both Y-direction end portions of the upper plate 32 of the first upper case 30a toward the -Z side. The pair of side plates 34 of the first upper case 30a cover both Y-direction outer surfaces of the pair of module side plates 116 of the first battery module 10a.

[0031] As shown in FIG. 2 , the first upper case 30a is at least partially located between at least a portion of the first battery module 10a and at least a portion of the pack housing 20. Specifically, the upper plate 32 of the first upper case 30a is located between the +Z side surface of the module upper plate 114 of the first battery module 10a and the −Z side surface of the pack upper plate 24a at a portion that overlaps with the first battery module 10a in the Z direction. When abnormal heat generation occurs in the battery cells 100 of the first battery module 10a, relatively high-temperature gas may be generated from the first battery module 10a. The module upper plate 114 of the first battery module 10a may have a gas exhaust portion, such as a gas hole, that exhausts gas generated from the first battery module 10a when abnormal heat generation occurs in the battery cells 100 of the first battery module 10a. If the module upper plate 114 of the first battery module 10a has a gas exhaust section, gas generated from the first battery module 10a may be blown toward the +Z side through the gas exhaust section provided in the module upper plate 114 of the first battery module 10a. In the embodiment, the upper plate 32 of the first upper case 30a serves as a partition member that separates the +Z side surface of the module upper plate 114 of the first battery module 10a from the −Z side surface of the pack upper plate 24a at a portion that overlaps with the first battery module 10a in the Z direction. Therefore, the upper plate 32 of the first upper case 30a can diffuse the gas generated from the first battery module 10a. Therefore, the upper plate 32 of the first upper case 30a can prevent the gas generated from the first battery module 10a from being blown directly toward the pack upper plate 24a when abnormal heat generation occurs in the battery cells 100 of the first battery module 10a. Therefore, in this embodiment, the heat resistance of the battery pack 1 can be improved compared to a case where the upper plate 32 of the first upper case 30a is not provided.

[0032] Relatively high-temperature gas is blown onto the upper plate 32 of the first upper case 30a from the first battery module 10a. Therefore, it is preferable that the upper plate 32 of the first upper case 30a be heat-resistant. The upper plate 32 of the first upper case 30a may include, for example, steel such as stainless steel. Steels such as stainless steel have a relatively high melting point. Therefore, if the upper plate 32 of the first upper case 30a includes steel such as stainless steel, the heat resistance of the upper plate 32 of the first upper case 30a can be improved. To impart electrical insulation to the upper plate 32 of the first upper case 30a, the upper plate 32 of the first upper case 30a may include an insulating material such as glass fiber or ceramic. For example, the surface of the upper plate 32 of the first upper case 30a may be coated with an insulating material such as glass fiber or ceramic. Alternatively, the upper plate 32 of the first upper case 30a may be substantially entirely made of an insulating material such as glass fiber, ceramic, etc. Even when the upper plate 32 of the first upper case 30a contains an insulating material such as glass fiber, ceramic, etc., the heat resistance of the upper plate 32 of the first upper case 30a can be improved.

[0033] To allow gas generated from the first battery module 10a to escape, the first upper case 30a does not seal the first battery module 10a. For example, both ends of the first upper case 30a in the X direction may be open, with no side plates corresponding to the side plates 34 provided at both ends of the upper plate 32 of the first upper case 30a in the X direction. Alternatively, if the upper plate 32 of the first upper case 30a has a substantially rectangular shape when viewed from the Z direction, the upper plate 32 of the first upper case 30a may be supported by four pillars arranged at the four corners of the upper plate 32 of the first upper case 30a when viewed from the Z direction.

[0034] 2, the -Z side surface of the upper plate 32 of the first upper case 30a and the +Z side surface of the module upper plate 114 of the first battery module 10a are spaced apart from each other in the Z direction. Therefore, a space exists between the -Z side surface of the upper plate 32 of the first upper case 30a and the +Z side surface of the module upper plate 114 of the first battery module 10a. When a space exists between the -Z side surface of the upper plate 32 of the first upper case 30a and the +Z side surface of the module upper plate 114 of the first battery module 10a, the gas blowing from the first battery module 10a toward the +Z side when abnormal heat generation occurs in the battery cells 100 of the first battery module 10a can be more easily diffused by the upper plate 32 of the first upper case 30a, improving the heat resistance of the battery pack 1, compared to when the -Z side surface of the upper plate 32 of the first upper case 30a and the +Z side surface of the module upper plate 114 of the first battery module 10a are in direct contact with each other without a space between them.

[0035] 2, the +Z side surface of the upper plate 32 of the first upper case 30a and the −Z side surface of the pack upper plate 24a are spaced apart from each other in the Z direction, so there is a space between the +Z side surface of the upper plate 32 of the first upper case 30a and the −Z side surface of the pack upper plate 24a. When there is a space between the +Z side surface of the upper plate 32 of the first upper case 30a and the -Z side surface of the pack upper plate 24a, the upper plate 32 of the first upper case 30a can prevent gas generated from the first battery module 10a from being blown directly onto the pack upper plate 24a when abnormal heat generation occurs in the battery cells 100 of the first battery module 10a, thereby improving the heat resistance of the battery pack 1, compared to when the first upper case 30a is not present or when the +Z side surface of the upper plate 32 of the first upper case 30a and the -Z side surface of the pack upper plate 24a are in direct contact with each other without a space between them.

[0036] The structure of the first upper case 30a is not limited to the example shown in FIG.

[0037] For example, the -Z side surface of the upper plate 32 of the first upper case 30a and the +Z side surface of the module upper plate 114 of the first battery module 10a may be in direct contact with each other without a gap, as long as at least a portion of the -Z side surface of the upper plate 32 of the first upper case 30a and at least a portion of the +Z side surface of the module upper plate 114 of the first battery module 10a are separated from each other in the Z direction. Even if the -Z side surface of the upper plate 32 of the first upper case 30a and the +Z side surface of the module upper plate 114 of the first battery module 10a are in partial contact with each other, gas blowing from the first battery module 10a toward the +Z side when abnormal heat generation occurs in the battery cells 100 of the first battery module 10a can be diffused by the portion of the upper plate 32 of the first upper case 30a that is separated from the module upper plate 114 of the first battery module 10a in the Z direction. The +Z side surface of the upper plate 32 of the first upper case 30a and the -Z side surface of the pack upper plate 24a may be in direct contact with each other without a partial space, as long as at least a portion of the +Z side surface of the upper plate 32 of the first upper case 30a and at least a portion of the -Z side surface of the pack upper plate 24a are spaced apart from each other in the Z direction.

[0038] Instead of a single partition member such as an upper plate 32, a plurality of partition members overlapping in the Z direction may be provided between the +Z side surface of the module upper plate 114 of the first battery module 10a and the −Z side surface of the portion of the pack upper plate 24a that overlaps with the first battery module 10a in the Z direction. For example, a plurality of upper plates 32 may overlap with each other in the Z direction between the +Z side surface of the module upper plate 114 of the first battery module 10a and the −Z side surface of the portion of the pack upper plate 24a that overlaps with the first battery module 10a in the Z direction.

[0039] In the embodiment, the module upper plate 114 has a gas exhaust portion that exhausts gas generated from the first battery module 10a when abnormal heat generation occurs in the battery cells 100 of the first battery module 10a. However, a portion of the first battery module 10a other than the module upper plate 114 may have the gas exhaust portion. For example, the module side plate 116 on the -Y side of the first battery module 10a may have the gas exhaust portion. When the module side plate 116 on the -Y side of the first battery module 10a has a gas exhaust portion, the module side plate 116 on the -Y side of the first upper case 30a may serve as a partition member that prevents gas generated from the first battery module 10a from being directly blown onto the -Y side portion of the pack frame 22b when abnormal heat generation occurs in the battery cells 100 of the first battery module 10a.

[0040] Fig. 3 is a cross-sectional view of the battery pack 1A according to the first modified example of Fig. 2. The battery pack 1A according to the first modified example is similar to the battery pack 1 according to the embodiment, except for the following points.

[0041] As shown in FIG. 3 , each upper plate 32A may be suspended from the −Z side surface of the pack upper plate 24a toward the −Z side by a support portion 34A. Each upper plate 32A is located between the +Z side surface of the module upper plate 114 of each battery module 10 and the −Z side surface of the pack upper plate 24a at the portion overlapping each battery module 10 in the Z direction. In the example shown in FIG. 3 , each upper plate 32A also serves as a partition member that separates the +Z side surface of the module upper plate 114 of each battery module 10 from the −Z side surface of the pack upper plate 24a at the portion overlapping each battery module 10 in the Z direction. Therefore, in the example shown in FIG. 3 , the heat resistance of the battery pack 1A can be improved compared to when each upper plate 32A is not provided.

[0042] Fig. 4 is a cross-sectional view of a battery pack 1B according to the second modified example of Fig. 2. The battery pack 1B according to the second modified example is similar to the battery pack 1 according to the embodiment, except for the following points.

[0043] As shown in FIG. 4 , the upper plate 32B may be supported on the pack frame 22b by a support portion 34B. In the example shown in FIG. 4 , the upper plate 32B covers the +Z side portions of both the first battery module 10a and the second battery module 10b. In the Z direction, the upper plate 32B is located between the +Z side surface of the module upper plate 114 of each battery module 10 and the −Z side surface of the pack upper plate 24a at the portion overlapping each battery module 10 in the Z direction. In the example shown in FIG. 4 , each upper plate 32B also serves as a partition member separating the +Z side surface of the module upper plate 114 of each battery module 10 from the −Z side surface of the pack upper plate 24a at the portion overlapping each battery module 10 in the Z direction. Therefore, in the example shown in FIG. 4 , the heat resistance of the battery pack 1B can be improved compared to when the upper plate 32B is not provided.

[0044] Although the embodiments and modifications of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted.

[0045] This application claims priority based on Japanese Patent Application No. 2023-148957, filed September 14, 2023, the disclosure of which is incorporated herein in its entirety by reference.

[0046] REFERENCE SIGNS LIST 1, 1A, 1B battery pack, 10 battery module, 10a first battery module, 10b second battery module, 10c third battery module, 10d fourth battery module, 20 pack housing, 22 pack lower case, 22a pack lower plate, 22b pack frame, 24 pack upper case, 24a pack upper plate, 24b pack upper side cover, 26 pressure release valve, 30 upper case, 30a first upper case, 30b second upper case, 32, 32A, 32B upper plate, 34 side plate, 34A, 34B support portion, 100 battery cell, 110 module housing, 112 module lower plate, 114 module upper plate, 116 module side plate

Claims

1. A battery pack comprising: a battery module; a housing that houses the battery module; and a partition member that is at least partially positioned between at least a portion of the battery module and at least a portion of the housing.

2. The battery pack according to claim 1, wherein said partition member is spaced apart from at least one of said at least a portion of said battery module and said at least a portion of said housing.

3. A battery pack as described in claim 1 or 2, wherein a space exists at least either between the partition member and at least a portion of the battery module, or between the partition member and at least a portion of the housing.

4. The battery pack according to any one of claims 1 to 3, wherein the partition member has heat resistance.

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